Merocyanine sensitizing dyes and sensitized photographic emulsions



Ferties.

United States Patent O A3,033,681 l vlVlERCYANll`IE -SENSITIZING SENSI-I1`IZED PHOTOGRAPHIC EMULSIONS y l 'Edwin-dB. Knott,`Wealilstone,-Eng`lai1il, assignor to Eastman Kodak "Company, Rochester,N.Y., a corporation of New Jersey f -Filed Jan. :19, 1959,` Ser. ENQ.787,493 -16 Claims. (Cl. 96102) This invention relates to novellpolymethine dyes of the merocyanine class, methods for making suchdyes, and photographic silver 'halide emulsions sensitized by means ofsuch polymethine dyes;

Polymethine dyes of the merocyanine types have been previouslydescribed, wherein the molecule contains a variety -of Vacidicheterocyclic nuclei. `1I hav'e ifound a fnew class rof .fmerocyanineldyes containinga complex acidic nucleus, the nitrogen-atom ofwhichcanfbe quaternated .to provide derivatives which .also'haveusefulprop- Many of the dyes described Yin Ithe ffollowing examples are usefulin increasing the 'sensitivity ofpho'tographic silver halide emulsions.

lt is, therefore, an lobject of my invention to provide a new class ofmerocyanine dyes. Another object lis fto provide methods `for makingsuch merocyanine dyes. Still .another object is toprovide -quaternatedderivatives of the aforesaid merocyanine dyes and-a method Afor makingsuch quate'rnated derivatives. Yet, another `object of my invention isto provide photographic silver halide emulsions spectrally sensitizedwith the new merocyanine dyes Eof my invention. Other objects willbecome apparent from a considerationof fthe following description andexamples.

My new merocyanine dyes can frequentlyh'e employed in sensitizingphotographic silver halide emulsions to a useful degree, and the eiectof three of these dyes of my invention in conventional photographicsilver halide emul- .sions'is illustrated diagrammatically inFIGU-RES A1to A3 -of the accompanying drawing. Further 'details .regard- .ing thiseiect are Jgiven below.

The V:new merecyanine dyes of my :invention include dyes represented :by:the `followingpgeneral:formulas:l

substituents, such as .alkoXyl (eg, methoxyl, ethoxyl,

'etc.), alkyl (e.g., methyl, ethyl, etc.), etc., -m represents apositive integer -of from l -to -2 land Z represents .the non-metallicatoms necessary Lto complete4 a heterocyclic nucleusicontaining from 5to6 atoms in thcsheterocyclic ring, such as those selected from the groupconsisting 3,033,681 Patented May l8, 1962 2 dimethylthiazole,4,5-diphenylthiazole, 4-(2thienyl)t hi azole, etc.), a benzothiazolenucleus (e.g., benzothiazole, 4-chlorobenzothiazo1e,S-chlorobenzothiazole, 6oh1oro benzothiazole, 7-ch1orobenzothiazole,4-rnethylbenzothiazole, .5-methylbenzothiazole, -methylbenzothiazole, 5-bromobenzothiazold G-bromobenzotliiazole,4 4-,phenylbenzothiazole,5-phenylbenzothiazle, 4-methoxybenzofthiazole, 5-methoxybenzothiazole,-rnethoxybcnzothiazole, 5-iodobenzothiazole, -iodobenzothiazole 4ethoxybenzothiazole, 5-ethoxybenzothiazole, .tetrahydrobenzothiazole,5,6-d`unethoxybenzothiazole, lf-diogrymethylenebenzot-hiazole,5-hydroxybenzthiazole, 6-hydroxybenzothiazole, etc.), anaphthothi'azolenucleus (e.g., naphtho'[1,2]-thiafzole, n'aphtho[2,=1`|thiazole, 5methoxynaph tho[2,1 thiazole, Seethoxynaphtho [2, 1thiazole, S-methoxynaphtho[1,2]thia zole, 7 methoxynaphtho[1,21thiazole, etc.), a thianaphtheiio7,'r6v,2t,5thiazdle "nucleus '(egg.,Ztmethoxythianap'htheno 7",6,'21,5=thiazle, etc.), an oxazole nucleus(e.g., '4im`ethyloXazole, 'Sl'm'ethyloXazole, 4fphenyloxazole,v'4,"5"diphenyl'oxazole, 4'ethyl ioxazole, 4,5-dimethyloiiazo'le,`5fphenyloxazole, etcf), Ya benzoxazole nucleus (e.g., ben'zoXazole,5-'ch1'orobenzoxazole, 5-methylbenzo'xa'zole, 5,-phenylb`enzoxazole, "6-methylbenzoxazle, "5,6 dimetliy'lbenzoxazdle, 4,6-"dimethylbenzoxazlefSmethoxybenzoxazole, 5 -ethoXyf'benzoxazole, S-chlorobenzoxazole,lG-methoxyhe'rizc'jxazole, 5-hydroxybenzoxazole, `6hydroxybenzoxazol'e,Aetc.), a naphthoxazole nucleus (eg, naphtho[1,`2]oxajz'ole,naphtho['2,1]oxazole, etc.l), a vsele'na'zole nucleus '(e.`g.'l-methylselenazo'le, 4&phenylselenazdl'e, et'cj), a vb`enzoselenazolenucleus v(eig, 'benzoselenazole S-,chlorobenzoselenazole,`5-methoxybenzoslenazle, '5-'l1`ydroxybenzoselenazle,tetrhydrobenzoselenazole, etc.), a naphthosele'nazole nucleus (-e.g.,naphtho`[l,2 selenazole, naphtho[2,l]se`le`nazo'le, etc.), a thiazolinenucleus (le.g.,-lth azoline,f4-methylthiazline, etc.), a 2-qu`ino'line.nucleus -(e.g., quinoline, S-methylqm'nline, "S-methylquinoline,y7kmethylquinoline, 8-methylquinoline, '-clfloroquinoline,

8-chloroquinoline, -methoxyquin'oline, -ethoxyquino- (IIa) RV-X1 whereinR2 and X1 have the values given above. The technique of quaternation iswll known and is illustrated `with respect *to :the present invention in'the .fdllowing examples. l y p "The merocyanine dyes of Formula above,wherein R1 represents 'a ihydro'genfatom canbeiprepared by*c'ondens'in'g a `compound 'selected from those represented iby the'following general formula:

:.(III) wherein R, m and Z each have the 'values given above, R3represents an acyl group (e.-g., acetyL-'proponyL lbutyryl,

benzoyl, etc.), Rrepres'entsfanraryl group (e.\g., phenyl, i

tolyl, etc.) and X represents an :acid radical or anion,

such as those listed above with respect to X1, with a compound selectedfrom those represented by the following wherein R, R1, X, m and Z eachhave the values given above, and R5 represents an alkyl group (e.-g.,methyl, ethyl, etc.), or an aryl group (e.g., phenyl, tolyl, etc.) witha compound of Formula IV.

In general, the condensation of the compounds of Formula III or FormulaIIIa with those of Formula 1V can be accelerated by heating, althoughtemperatures from ambient temperatures (ca. 20 C.) to the refluxtemperature of the reaction mixture, can be employed. Also, thecondensations can becarried out in the presence of an inert solvent, ifdesired; Typical inert solvents include pyridine, benzene, ethanol,propanol, isopropanol, butanol, isobutanol, etc. The condensations canbe accelerated further -by means of a basic condensing agent, such `asthe lower trialkylamines (e.g., triethylamine, tripropylamine,triisopropylamine, tributylamine, triisobutylamine, etc.), theN,Ndialkylanilines (e.g., dimethylaniline, diethylaniline, etc.), theN-alkylpiperidines (e.g., N-methylpiperidine, N -ethylpiperidine,vetc.), etc.

The intermediates of Formula IV above can be prepared by heatingtogether a compound of the following general formula:

D o-Nncnzcoorr wherein D has lthe values given. above with an acidiccondensing agent, such as phosphorus trichloride. The ring formation ofthe compounds of -Formula V can be carried out in the presence of aninert diluent, such as dioxan, dethyl ether, etc.

The compounds of Formula V above can advantageously be prepared by.heating glycine in an alkaline medium containing a compound of thefollowing general formula:

s D; \o-na1 Example 1.-,-N-Benzothazol-2-Ylglycne C-NHCHzCOOH2-chlorobenzothiazo1e (8.5 g.) was added to a solution of potassiumhydroxide (5.6 g.) and glycine (7.5 g.) in Water (50 cc.). Triethylamine(7.5 cc.) and ethanol (50 cc.) were added and the whole was reuxed for24 hours. The solution was evaporated to dryness. 'Ihe residue wasboiledup with ethanol and the solid collected. It (7.0 g., 67%) formedfelted needles from water or ethylene glycol, M.P. 20L-202 C.

Example 2.-2:3'-Dhydro-S-Oxobenzothiazole- 2 :3 '-2 :1-Glyoxaline Hydroch lorde N-benzothiazolylglycine (1.05 g.) was covered with dioxan(l0 cc.) and phosphorus trichloride (5 cc.) was added and the Wholereuxed on a steam bath for 30 minutes. The glycine softened thenresoliditied. The solvent was decanted and the solid Washed with etherand was used directly in the dye condensations.

The use of phosphorus tribrornide instead of the trichloride results inthe formation of the corresponding hydrobromide.

The product of Example 2 (from 1.05 g. of N-benzotbiazol 2ylglycine),2-(2acetanilidovinyl) 3ethylbenz oxazolium iodide (2.1 g.), ethanol (20cc.) and triethyllamine (3 cc.) were relluxed together for 15 minutes.The dye was collected after chilling, extracted with hot benzene, thebenzene solution was concentrated to 10 cc. and hot ethanol (20 cc.) wasadded. The dye (0.6 g.) formed orange crystals, M.P. 268 C.

It sensitized a silver chlorobromide emulsion with a peak at 530 mp.extending to 580 mu and a silver iodobromide emulsion with a peak at 530ma extending to 570 mp. when added at a rate of 0.1 g./mole silverhalide.

emulsions with'a peak at 540 my extending to 560 mit.

separated were 4recrystallized from methanol-ether. required iodide (0.4g., 46.5%) formed line orange threads, NLP. 263 C.

Sensitizing data were very similar to those of Example -4.

The product of Example 2 (froml 4.2 g. of .N-benzon`thiazol-2-ylglycine), 2-(2acetanilidovinyl)3-methyl thiazolinium iodide(7.8 g.), nitrohenzene (20 cc.) and tri- -ethylarnine (6 cc.) wereheated togetheron a steambath Ethanol (40 cc.) was added and the vIt.(4.4 g., 70%) was dissolved in for 40rminutes. dye Was collected.

pyridine (10 cc.) and hot ethanol (25 cc.) added. The

rust -needles (1.85 g., 29%) which separated had NLP.

-At 0.1 g./1nole silver halide it sensitized a silver chlorobromideemulsion with a peak at 530 ma extending to 560 mp. and a silveriodobromide emulsion with a peak Thefproductf-oLExample 6 (1.05g.) andmeth-ylsulfate v(11.5 ce.) were fused at v130 lC. for 10 minutes. The

v'quaternized 4dye was Washed with benzene 4dissolved -in vvmethanol`(25 cc.),ethanol (15 .cc.-) was addedandthe fsolution thenvconcentrated Vto 15 cc.

:extending to 540 my. amd a silver iodobromide with a .peak at -510 kmaextending to 540 mp..

concentrated until crystallization V'set in.

. v 6 The product of Example 2 (from 2.2 g. ofN-benzothiazol-Z-ylglycine) 2`,2anilinovi'nyl3-ethy1-4:5diphenylox-azolium toluene-p-sulfonate (5.5 'g.)., nitrobenzene (40 ce),triethylamine '(8 ce), and 'acetic Vanhydride '(1.5 cc.) were heatedtogether on a steam bath for 40 minutes. Ethanol (l00`cc.) `was addedand the Wholechlled `for 3 days. ll`herequired dye (1.11g.) "separated.and :formed red or yellow :needles :from pyridine-ethanol or Aorangeprisms from benzene, decompi. 247 C. onwards. Example9.-4-(3Ethyl4:5-Diphenyloxazolin-ZYlidene- Ethylderie) 2z3Dhydro--Methyl-5-0x0benzothazolo-Z':32:14Gly0xalniam Iodde The productvof Example `8 (0.1"5 g.) and methylltolu- Aene-psulfonate (0.15 g.)were fused togetherat '120'C.

for 30'minutes. The quaternized'base Was then dissolved in etihanol,filtered Vand la 'satunat'ed aqueous 'potassium iodide solution (0.1cc.) was added. The 'dye iodide vwhich 4Jhad 'precipitated Was dissolvedin methanol, and `an equal volume'ofethanol `was added and 4the-`sc`lution YIt (0.14 g., 71%) formed orange prisms, M.P.'282 =C.

At f0.1 g./rnle silver 4@halide it sensitized `strongly va silverchlorobromide emulsion with ape'ak at 530 ma extending to 560 ma 'and asilver iodobromide emulsion with a'pea'li at 540 myfextending to 560my..

Example 0.*i-6-Etl10xy-N-BenzotliiazolfZ-Ylglycine CgHaO-f 'i 1 C-NHCHaCO OH Potassium hydroxide (4196 fg.) was dissolved'inuvvater (45 lcc.),glycine i(6.6 g..) and 2-ch1o1'0-6-ethoxybenzo- `thiazo'le (M.P. 65-'67lC.,1cf. J.-Amer.-Chem. Soc., `1949, 7l, 3417) -(9.5g.) wereadded"followedbyitriethylamine 1(6.6cc.) vand-ethanol (45 cof).A'flaefvvhle'was reuxed on a steam bath for 8 days whenafsa'mple-rem'ainedclear on dilution ywith Water. Thes'olve'nt Was'removed lunder reduced pressure,ethanl (.20 cc.) 'was.added, boiled 'upand the Vsalts were fcolilected. They 'were dissolved .in Water (65 cc.)andglacial 'acetic acidf,(5.i3 cc.)` Wasnadded 'to givea -whitecrystallinemeal. From ethanol the hydrate formed White vcrystals aMiP.S153'o C. (depending on the rate offheating)fthemeltIresolidiedidarkened at Ica. V265 C. Yield4.75 g.

Yethylamine (5cc.) were ad'dedandthe'whole'Washeated 'for one 'hour on asteam bath. Ethanol (70 ce.) was added and the llask'was `chilledovernight. lThe'dye was collected and extracted in aSoxhletlthiible'withben'zene.

7 The benzene-soluble dye was collected after chilling and frompyridine-methanol it (0.8 g.) formed a brick-red powder M.P. 271 C.(previous softening).

The product of Example 1l (0.8 g.) and methyl sulfate (1 cc.) were fusedtogether at 120 C. `for 10 minutes. The whole solidied after 2-3minutes. The solid quaternary salt was dissolved in boiling methanol,the solution was iiltered from any uuquaternized dye and an equalwashed, finished emulsion and should, of course, be uniy formlydistributed throughoutthe emulsion. In the preparation of photographicemulsions containing my new dyes, it is only necessary to disperse thedyes in the emulsions. The methods of incorporating dyes in emulsion aresimple and well known to those skilled in the art of emulsion making. Itis convenient to add the dyes from solutions in appropriate solvents.The solvent must, of course, be compatible with the emulsion andsubstantially free from any deleterious eiect on the light-sensitivematerials. Pyridine has proven satisfactory as a solvent for many of mynew dyes.

The concentration of my new dyes in the emulsion can vary widely, i.e.,from about 5 to about 200 mgs. per liter of tiowable emulsion. Theconcentration of the dye will vary according to the type oflight-sensitive material in the emulsion and according to the eiectsdesired. The suitable and most economical concentration -for any givenemulsion will be apparent to those skilled in the art upon making theordinary tests and observations customarily used in the art of emulsionmaking.

To prepare a gelatino-silver-halide emulsion sensitized with one of mynew dyes, the following procedure is satisfactory: A quantity of the dyeis dissolved in pyridine or other suitable solvent and a volume of thissolution (which may be diluted with methanol) containing from 5 to 200mgs. of dye is slowly added to about 1000 cc. of agelatino-silver-halide emulsion, with stirring. Stirring is continueduntil the dye is uniformly distributed throughout the emulsion. Withmost of my new dyes, to 100 mgs. of dye per liter of emulsion suices toproduce the maximum sensitizing effect with the ordinarygelatino-silver-bromide (including bromiodide) emulsions. Withfine-grain emulsions, which include most of the lordinarily-employedgelatino-silver-chloride emulsions,

somewhat larger concentrations of dye may be necessary to secure theoptimum sensitizing etect.

The above statements are only illustrative and are not to be understoodas limiting my invention in any sense, as it will be apparent that mynew dyescan be incorporated by other methods in many of the photographicsilver halide emulsions customarily employed in the art. For

instance, the dyes can be incorporated by bathing a plate or iilm uponwhich an emulsion has been coated, in the solution of the dye, in anappropriate solvent. Bathing methods, however, are not to he preferredordinarily.

Photographic silver halide emulsions which can advantageously besensitized by means of the new dyes of my invention comprise thecustomarily-employed gelatinesilver-chloride,gelatino-silver-ch1orobromide, gelatinosilver-bromide, andgelatino-silVer-bromiodide developingout emulsions.

Photographic silver halide emulsions such `as those listed above,containing the sensitizing dyes of my invention can Ialso contain suchaddenda as chemical sensitizers, eg., sulfur sensitizers (e.g., allylthiocarbamide, thiourea, allylisothiocyanate, cystine, etc.), variousIgold compounds (e.g., potassium chloroaurate, auric trichloride, etc.)(see U.S. patents W. D. Baldsiefen 2,540,085, granted February 6, 1951;R. E. Damschroder 2,597,856, granted May 27, 1952, Vand H. C. Yutzy etal. 2,597,915, granted May 27, 1952), various palladium compounds, suchas palladium chloride (W. D. Baldsiefen U.S. 2,540,086, granted February6, 1951), vpotassium chloropalladate (R. E. Stauier et al. U.S.2,598,079, granted May 27, 1952), etc., or mixtures of such sensitizers;-antifoggants, such as yammonium chloroplatinate (A. P. H. Trivelli etal. U.S. 2,566,245, granted August 28, 1951), ammonium chloroplatinite(A. P. H. Trivelli et al. U.S. 2,566,263, granted August 28, 1951),benzotriazole, nitrobenzimidazole, S-nitroindazole, benzidine,mercaptans, etc. (see Mees-The Theory of the Photographic Process,Macmillan Pub., 1942, page 460), or mixtures thereof; hardeners, such asformaldehyde (A. Miller U.S. 1,763,- 533, granted June l0, 1930), chromealum (U.S. 1,763,- 533), glyoxal (J. Brunken U.S. 1,870,354, grantedAugust 9, 1932), dibromacrolein (O. Block et al. Br. 406,750, acceptedMarch 8, 1934), etc.; color couplers, such as those described in I. F.Salminen et al. U.S. Patent 2,423,730, granted July 7, '1947, Spence andCarroll U.S. Patent 2,640,776, issued June 2, 1953 etc.; or mixtures ofsuch addenda. Dispersing agents for color couplers, such `as those setforth in 'U.S. patents E. E. Jelly etal. 2,322,027, granted .Tune 15,1943, and L. D. Mannes et al. 2,304,940, granted l'December 15, 1942,can also be employed in the above-described emulsions.

The accompanying drawing further illustrates my invention. Each ligureis a diagrammatic reproduction of la spectrogram showingv thesensitivity of an ordinary gelatino-silver-chlorobromide emulsioncontaining one of my new sensitizing dyes. In FIGURE l, the curvedepicts a sensitivity of `an ordinary gelatino-silver-chlorobromideemulsion containing 4-(3-ethylbenzoxazolin-2-ylidene-ethylidene)-2':3'dihydro 5 oxobenzothiazole- 2:3'2:1glyoxaline.The preparation of this dye is illustrated in Example 3 above.

In FIGURE 2, the curve depicts the sensitivity of an ordinarygelatino-silver-chlorobromide emulsion containing 4-(3-ethylbenzoxazolin2-ylidene-ethy1idene) 2:3 dihydro-S-methyl 5 oxobenzothiazolo 2'132:1-g1yoxalinium methylsulfate. The preparation of this dye isillustrated in Example 4 above.

In FIGURE 3, the curve depicts the sensitivity of an ordinarygelatino-silver-chlorobromide emulsion containing 4-(3-methylthiazolidin2 ylidene-ethylidene) -2':3 dihydro-S oxobenzothiazolo2:3'2:1glyoxaline. The preparation of this dye is illustrated in Example6 above.

The invention has been described in detail with -particular reference topreferred embodiments thereof, but it will be understood that variationsand modifications can be effected within the spirit and scope of theinvention as described hereinabove and as dened in the appended claims.

What I claim as my invention `and desire secured by Letters Patent ofthe United States is:

1. A photographic silver halide emulsion sensitized -9 a merocyanine dyeselected Afrom the class consisting of those represented by thefollowing general formulas:

and

Z"` 0=O^N j R-NoH=on)m`1`-`o=oH-o- @y l1 \N// S VR54/ \X1 wherein R andR2 each represents an alkyl group containing from l to 7 carbon atoms,R1 represents a member selected from the class consisting of .a hydrogenatom, a lower alk-yl groupland :an aryl group, X1 represents kan acidradical, D represents the atoms necessary to complete a monocyclicarylene group containing from 6 to 8 carbon atoms, m represents apositive integer o-f from 1 to 2 and Z represents the non-metallic atomsnecessary to complete a'heterocyclic nucleus selected from the classconsisting of a thia'zole nucleus, a benzothiazole nucleus, anaphthothiazole nucleus, a thianaphtheno-7',6,4,5 thiazole nucleus, anoxazole nucleus, a benzoxazole nucleus, a naphthoxazole nucleus, aselenazole nucleus, a benzoselenazole nucleus, a naphthoselenazol'enucleus, a thiazoline nucleus, a 2-quinoline nucleus, a 4-quino1inenucleus, a l-isoquinoline nucleus, a benzimidazole nu cleus, a3,3-dialkylindolenine nucleus, a Z-pyridine nucleus and a 4-,pyridinenucleus s 2. A photographic silver halide emulsion as delined in claim"1 wherein said silver halide is silver chloro- .bromide.

. 3. A photographic silver halide emulsion as delined in claim l whereinsaid silver halide is silver iodobromide.

4. A photographic silver 'halide developing-out emulsion sensitized witha merocyanine dye selected from those represented by the followinggeneral formula:

wherein R represents an -alkyl group containing from 1 to 7 carbonatoms, R1 represents a member selected from the class consisting of ahydrogen atom, a lower alkyl group and a monocyclic aryl group of thebenzene series, D represents the atoms necessary to complete a monocyclcarylene group containing from 6 to 8 carbon atoms, and Z represents thenon-metallic atoms necessary to complete a heterocyclic nucleus selectedfrom the class consisting of those of the benzoxazole series, thoseofthe thiazoline series and those of the oxazole series.

5. A photographic silver halide developing-out emulsion sensitized witha merocyanine dye selected from those represented by the followinggeneral formula:

' thiazoline series and those of lthe oX-azole series.

l0 6. Aphotographic silver'halide developing-out emulsion sensitizedwith a merocyanine dye selected from those represented by the followinggeneral formula:

wherein "R Vrepresents an alkyl group containing'from 'l 'to 8. Aphotographic silver halide developingeout emul-A sion sensitized with amerocyauine dye selected `from lthose represented bythe followinggeneral formula:

wherein Rand R2 each represents an alkyl group contain- 4ing from l to 7carbon atoms, R1 represents a member selected from lthe class consistingof a hydrogen atom, a lower alkyl V"group anda monocyclie aryl group ofthe benzene series, X1 represents an acid radical, D represents theatoms necessary (to complete a monocyclic arylene group containing from6 to 8 carbon atoms and Z represents the Anon-metallic atoms necessaryto complete a heterocyclic nucleus of the benzoxazole series.

9. A photographic halide developing-out emulsion sensitized with amerocyanine dye represented by the following formula:

10. A photographic halide developing-out emulsion sensitized with amerocyanine dye represented by the following formula:

-l1. 'A photographic silver halide developing-out emulsion sensitizedwith a merocyanine dye selected from those represented by the followinggeneral formula:

wherein R represents an alkyl ygroup containing from 1 to 7 carbonatoms, R1 represents a member selected from 11 Y the class consisting ofa hydrogen atom, a lower alkyl group and a monocyclic arylgroup of thebenzene series, D represents the atoms necessary to complete amonocyclic arylene group containing from 6 to 8 carbon atoms,

13. A photographic silver halide developing-out emulsion sensitized witha merocyanine dye selected from those represented by the followinggeneral formula:

Rr/ \Xx wherein R and R2 each represents an Aalkyl group containing from1 to 7 carbon atoms, R1 represents a member selected from the classconsisting of a hydrogen atom, a lower alkyl group and a monocyclic arylgroup of the benzene series, X1 represents an acid radical, D representsthe atoms necessary to complete a monocyclic arylene group containingfrom 6 to 8 carbon atoms and Z represents the non-metallic `atomsnecessary to complete a heterocyclic nucleus of the thiazoline series.

14. A photographic silver halide developing-out emulsion sensitized witha merocyanine dye represented by the following formula:

12 15. A photographic silver halide developingout emulsion sensitizedwith a merocyanine dye selected from those represented by the followinggeneral formula:

wherein R represents an `alkyl group containing from 1 to 7 carbonatoms, R1 represents a member selected from the class consisting of ahydrogen atom, a lower alkyl group and a monocyclic aryl group of thebenzene series, D represents the atoms necessary to complete amonocyclic arylene group containing trom 6 to 8 carbon atoms, and Zrepresents the non-metallic atoms necessary to complete a heterocyclicnucleus of the oxazole series.

16. A photographic silver halide developing-out emulsion sensitized witha merocyanine dye represented by the following formula:

VBrooker et al. July 11, 1939 2,216,441 Keyes Oct. 1, 1940 2,464,780Anish Mar. 22, 1949 2,514,649 Knott July 11, 1950 2,706,193 Sprague Apr.12, 1955 2,739,147 Keyes Mar. 20, 1956 OTHER REFERENCES ChemicalAbstracts, 16, p. 3101. Abstract of Med. Journal, 1922, I, pp. 514-515.

Chemical Abstracts, 19, p. 530. Abstract of Pros. Roy. Soc., London,96B, pp. 317-333, 1924.

Brit.

UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION corrected below.

Column ll, lines lO to 151, the left-hand portion of the formula shouldappear as shown below instead of as in the patent:

H20 2 N I CH3 same column l1, lines 2O to 25, the right-hand portion ofthe formula should appear as shown below instead of as in the patent:

`N Hz l D S Signed and sealed this 18th day of September 192 (SEAL)Attest:

ERNEST W. SWIDER DAVID L. LADD `htesting Officer Commissioner of Patents

1. A PHOTOGRAPHIC SILVER HALIDE EMULSION SENSITIZED WITH A MEROCYANINEDYE SELECTED FROM THE CLASS CONSISTING OF THOSE REPRESENTED BY THEFOLLOWING GENERAL FORMULAS: